Geomagnetic Storms:Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm

Updated at: 2016 Aug 09 2200 UTC

Mid-latitudes

0-24 hr

24-48 hr

ACTIVE

30 %

20 %

MINOR

05 %

05 %

SEVERE

01 %

01 %

High latitudes

0-24 hr

24-48 hr

ACTIVE

20 %

20 %

MINOR

35 %

30 %

SEVERE

30 %

25 %

Tuesday, Aug. 9, 2016

What's up in space

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PERSEID METEOR OUTBURST: The Perseid meteor shower peaks this week, and it could be twice a good as usual. Forecasters say the meteor rate could surge to 200+ meteors per hour on Aug. 11-12. Click here for the full story.

SPECTACULAR SOLAR PROMINENCE: An enormous filament of magnetism is snaking over the sun's eastern limb. "It's huge," says astronomer Jack Newton, who photographed the prominence from his private observatory in Osoyoos, British Columbia:

Alan Friedman saw the same structure from Buffalo, New York: photo. "It is at least as long as the distance from Earth to the Moon," he says.

This is a type of prominence commonly called a "hedgerow prominence." Hot glowing plasma inside the structure is held aloft by unstable solar magnetic fields. NASA and Japanese space telescopes have taken high resolution images of of similar prominences and seen some amazing things such as (1) tadpole-shaped plumes that float up from the base of the prominence; (2) narrow streams of plasma that descend from the top like waterfalls; and (3) swirls and vortices that resemble van Gogh's Starry Night.

NOCTILUCENT CLOUDS, WANING YET STILL IMPRESSIVE: August is the month when noctilucent clouds (NLCs) typically begin to wane. Indeed, images from NASA's AIM spacecraft show the electric-blue oval around the north pole is beginning to recede. Nevertheless, high-latitude sky watchers are still seeing some impressive displays. Ruslan Merzlyakov sends this picture from Road E4, near Umeå, Sweden:

"After 12 hours of driving back home from Nordkapp, I saw the most beautiful noctilucent clouds on August 7th," says Merzlyakov. "This was absolutely spectacular!"

If noctilucent clouds look alien, that's because they are--in part. A key ingredient is meteoroids from deep space. These clouds form when wisps of summertime water vapor rise up to the mesosphere and wrap themselves around specks of meteor smoke. The resulting ice crystals glow electric-blue when they are hit by the rays of the high-altitude sun: diagram.

This summer season of NLCs is almost over. Browse the photo gallery for last-chance sightings.

CAPT. KIRK AT THE EDGE OF SPACE: Where Spock goes, Kirk must follow. To celebrate the 50th Anniversary of Star Trek and to support their crowdfunded research program, the students of Earth to Sky Calculus launched the captain of the Enterprise to the stratosphere on July 27, 2016. Note the moon over Kirk's shoulder in this photo taken 36 km (118,100 ft) above Earth's surface:

Proceeds from the sale support space weather research. Bobblehead Kirk hitchhiked on a helium balloon payload that carried an array of X-ray/gamma-ray sensors. By launching these sensors 3 or 4 times a month, the students have shown that cosmic rays are intensifying--a trend that affects mountain climbers, air travelers, high-altitude drones, and astronauts on the International Space Station.

Every night, a network of NASA all-sky cameras scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near Earth Asteroids

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

These measurements are based on regular space weather balloon flights: learn more.

Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly "space weather balloons" to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. For example, here is the data from a flight on Oct. 22, 2015:

Radiation levels peak at the entrance to the stratosphere in a broad region called the "Pfotzer Maximum." This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are more than 80x sea level.

Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Oct 22th measurements, a plane flying at 45,000 feet is exposed to 2.79 uSv/hr. At that rate, a passenger would absorb about one dental X-ray's worth of radiation in about 5 hours.